Detected by CoverityScan CID#1438719 ("Unused Value")
buf is reset again before being used so these two lines of code
are useless.
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Every time after a session reconnect we don't need to account for
credits obtained in previous sessions. Introduce new struct cifs_credits
which contains both credits value and reconnect instance of the
time those credits were taken. Modify a routine that add credits
back to handle the reconnect instance by assuming zero credits
if the reconnect happened after the credits were obtained and
before we decided to add them back due to some errors during sending.
This patch fixes the MTU credits cases. The subsequent patch
will handle non-MTU ones.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently we set reconnect instance to zero on the first
connection but this is not convenient because we need to
reserve some special value for credit handling on reconnects
which is coming in subsequent patches. Fix this by starting
with one when initiating a new TCP connection.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Even if a response is malformed, we should count credits
granted by the server to avoid miscalculations and unnecessary
reconnects due to client or server bugs. If the response has
been received partially, the session will be reconnected anyway
on the next iteration of the demultiplex thread, so counting
credits for such cases shouldn't break things.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
We negotiate rsize mounts (and it can be overridden by user) to
typically 4MB, so using larger default I/O sizes from userspace
(changing to 1MB default i/o size returned by stat) the
performance is much better (and not just for long latency
network connections) in most use cases for SMB3 than the default I/O
size (which ends up being 128K for cp and can be even smaller for cp).
This can be 4x slower or worse depending on network latency.
By changing inode->blocksize from 32K (which was perhaps ok
for very old SMB1/CIFS) to a larger value, 1MB (but still less than
max size negotiated with the server which is 4MB, in order to minimize
risk) it significantly increases performance for the
noncached case, and slightly increases it for the cached case.
This can be changed by the user on mount (specifying bsize=
values from 16K to 16MB) to tune better for performance
for applications that depend on blocksize.
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
We should add any credits granted to us from unmatched server responses.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
a trivial patch that replaces all use of snprintf with scnprintf.
scnprintf() is generally seen as a safer function to use than
snprintf for many use cases.
In our case, there is no actual difference between the two since we never
look at the return value. Thus we did not have any of the bugs that
scnprintf protects against and the patch does nothing.
However, for people reading our code it will be a receipt that we
have done our due dilligence and checked our code for this type of bugs.
See the presentation "Making C Less Dangerous In The Linux Kernel"
at this years LCA
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
There is a NULL pointer dereference of devname in strspn()
The oops looks something like:
CIFS: Attempting to mount (null)
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
...
RIP: 0010:strspn+0x0/0x50
...
Call Trace:
? cifs_parse_mount_options+0x222/0x1710 [cifs]
? cifs_get_volume_info+0x2f/0x80 [cifs]
cifs_setup_volume_info+0x20/0x190 [cifs]
cifs_get_volume_info+0x50/0x80 [cifs]
cifs_smb3_do_mount+0x59/0x630 [cifs]
? ida_alloc_range+0x34b/0x3d0
cifs_do_mount+0x11/0x20 [cifs]
mount_fs+0x52/0x170
vfs_kern_mount+0x6b/0x170
do_mount+0x216/0xdc0
ksys_mount+0x83/0xd0
__x64_sys_mount+0x25/0x30
do_syscall_64+0x65/0x220
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fix this by adding a NULL check on devname in cifs_parse_devname()
Signed-off-by: Yao Liu <yotta.liu@ucloud.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
When executing add_credits() we currently call cifs_reconnect()
if the number of credits is zero and there are no requests in
flight. In this case we may call cifs_reconnect() recursively
twice and cause memory corruption given the following sequence
of functions:
mid1.callback() -> add_credits() -> cifs_reconnect() ->
-> mid2.callback() -> add_credits() -> cifs_reconnect().
Fix this by avoiding to call cifs_reconnect() in add_credits()
and checking for zero credits in the demultiplex thread.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This debug message was never shown because it was checking for NULL
returns but extract_hostname() returns error pointers.
Fixes: 93d5cb517d ("cifs: Add support for failover in cifs_reconnect()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
When DFS is not used on the mount we should not be mentioning
DFS in the warning message on reconnect (it could be confusing).
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
In case a hostname resolves to a different IP address (e.g. long
running mounts), make sure to resolve it every time prior to calling
generic_ip_connect() in reconnect.
Suggested-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Fix potential NULL ptr deref when DFS target list is empty.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Start the DFS cache refresh worker per volume during cifs mount.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
A spin lock is held before kstrndup, it may sleep with holding
the spinlock, so we should use GFP_ATOMIC instead.
Fixes: e58c31d5e387 ("cifs: Add support for failover in cifs_reconnect()")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
After failing to reconnect to original target, it will retry any
target available from DFS cache.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This patch adds support for failover when failing to connect in
cifs_mount().
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This patch will make use of DFS cache routines where appropriate and
do not always request a new referral from server.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
* Add new dfs_cache.[ch] files
* Add new /proc/fs/cifs/dfscache file
- dump current cache when read
- clear current cache when writing "0" to it
* Add delayed_work to periodically refresh cache entries
The new interface will be used for caching DFS referrals, as well as
supporting client target failover.
The DFS cache is a hashtable that maps UNC paths to cache entries.
A cache entry contains:
- the UNC path it is mapped on
- how much the the UNC path the entry consumes
- flags
- a Time-To-Live after which the entry expires
- a list of possible targets (linked lists of UNC paths)
- a "hint target" pointing the last known working target or the first
target if none were tried. This hint lets cifs.ko remember and try
working targets first.
* Looking for an entry in the cache is done with dfs_cache_find()
- if no valid entries are found, a DFS query is made, stored in the
cache and returned
- the full target list can be copied and returned to avoid race
conditions and looped on with the help with the
dfs_cache_tgt_iterator
* Updating the target hint to the next target is done with
dfs_cache_update_tgthint()
These functions have a dfs_cache_noreq_XXX() version that doesn't
fetches referrals if no entries are found. These versions don't
require the tcp/ses/tcon/cifs_sb parameters as a result.
Expired entries cannot be used and since they have a pretty short TTL
[1] in order for them to be useful for failover the DFS cache adds a
delayed work called periodically to keep them fresh.
Since we might not have available connections to issue the referral
request when refreshing we need to store volume_info structs with
credentials and other needed info to be able to connect to the right
server.
1: Windows defaults: 5mn for domain-based referrals, 30mn for regular
links
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Different servers have different set of file ids.
After failover, unique IDs will be different so we can't validate
them.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
When extracting hostname from UNC, check for leading backslashes
before trying to remove them.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
* Split and refactor the very large function cifs_mount() in multiple
functions:
- tcp, ses and tcon setup to mount_get_conns()
- tcp, ses and tcon cleanup in mount_put_conns()
- tcon tlink setup to mount_setup_tlink()
- remote path checking to is_path_remote()
* Implement 2 version of cifs_mount() for DFS-enabled builds and
non-DFS-enabled builds (CONFIG_CIFS_DFS_UPCALL).
In preparation for DFS failover support.
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
To avoid the warning:
warning: this statement may fall through [-Wimplicit-fallthrough=]
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steve French <stfrench@microsoft.com>
Technically 3.02 is not the dialect name although that is more familiar to
many, so we should also accept the official dialect name (3.0.2 vs. 3.02)
in vers=
Signed-off-by: Kenneth D'souza <kdsouza@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull AFS updates from Al Viro:
"AFS series, with some iov_iter bits included"
* 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
missing bits of "iov_iter: Separate type from direction and use accessor functions"
afs: Probe multiple fileservers simultaneously
afs: Fix callback handling
afs: Eliminate the address pointer from the address list cursor
afs: Allow dumping of server cursor on operation failure
afs: Implement YFS support in the fs client
afs: Expand data structure fields to support YFS
afs: Get the target vnode in afs_rmdir() and get a callback on it
afs: Calc callback expiry in op reply delivery
afs: Fix FS.FetchStatus delivery from updating wrong vnode
afs: Implement the YFS cache manager service
afs: Remove callback details from afs_callback_break struct
afs: Commit the status on a new file/dir/symlink
afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS
afs: Don't invoke the server to read data beyond EOF
afs: Add a couple of tracepoints to log I/O errors
afs: Handle EIO from delivery function
afs: Fix TTL on VL server and address lists
afs: Implement VL server rotation
afs: Improve FS server rotation error handling
...
In network file system it is fairly easy for server and client
atime vs. mtime to get confused (and atime updated less frequently)
which we noticed broke some apps which expect atime >= mtime
Also ignore relatime mount option (rather than error on it) since
relatime is basically what some network server fs are doing
(relatime).
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
As we reset credits later in the reconnect path, useful
to have optional (cifsFYI) debug message.
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
tcon->Flags is only used by SMB1 code and changing it is not permanent
(you lose the setting on tcon reconnect).
* Move the setting to superblock flags (per mount-points).
* Make automount callback exit early when flag present
* Make dfs resolving happening in mount syscall exit early if flag present
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Each time we reconnect to the same server, bump an instance
counter (and display in /proc/fs/cifs/DebugData) to make it
easier to debug.
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.
Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements. This makes it easier to add further
iterator types. Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.
Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself. Only the direction is required.
Signed-off-by: David Howells <dhowells@redhat.com>
Fixes problem (discovered by Aurelien) introduced by recent commit:
commit b24df3e30c
("cifs: update receive_encrypted_standard to handle compounded responses")
which broke the ability to respond to some lease breaks
(lease breaks being ignored is a problem since can block
server response for duration of the lease break timeout).
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
cifs_delete_mid() is called once we are finished handling a mid and we
expect no more work done on this mid.
Needed to fix recent commit:
commit 730928c8f4
("cifs: update smb2_queryfs() to use compounding")
Add a warning if someone tries to dequeue a mid that has already been
flagged to be deleted.
Also change list_del() to list_del_init() so that if we have similar bugs
resurface in the future we will not oops.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
This patch is required allows access to a Microsoft fileserver failover
cluster behind a 1:1 NAT firewall.
The change also provides stronger context for authentication and share
connection (see MS-SMB2 3.3.5.7 and MS-SRVS 3.1.6.8) as noted by
Tom Talpey, and addresses comments about the buffer size for the UNC
made by Aurélien Aptel.
Signed-off-by: Thomas Werschlein <thomas.werschlein@geo.uzh.ch>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Tom Talpey <ttalpey@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Add tracepoints for reconnecting an smb3 session
Example output (from trace-cmd) with the patch
(showing the session marked for reconnect, the stat failing, and then
the subsequent SMB3 commands after the server comes back up).
The "smb3_reconnect" event is the new one.
cifsd-25993 [000] .... 29635.368265: smb3_reconnect: server=localhost current_mid=0x1e
stat-26200 [001] .... 29638.516403: smb3_enter: cifs_revalidate_dentry_attr: xid=22
stat-26200 [001] .... 29648.723296: smb3_exit_err: cifs_revalidate_dentry_attr: xid=22 rc=-112
kworker/0:1-22830 [000] .... 29653.850947: smb3_cmd_done: sid=0x0 tid=0x0 cmd=0 mid=0
kworker/0:1-22830 [000] .... 29653.851191: smb3_cmd_err: sid=0x8ae4683c tid=0x0 cmd=1 mid=1 status=0xc0000016 rc=-5
kworker/0:1-22830 [000] .... 29653.855254: smb3_cmd_done: sid=0x8ae4683c tid=0x0 cmd=1 mid=2
kworker/0:1-22830 [000] .... 29653.855482: smb3_cmd_done: sid=0x8ae4683c tid=0x8084f30d cmd=3 mid=3
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
We really, really want to be encouraging use of secure dialects,
and SMB3.1.1 offers useful security features, and will soon
be the recommended dialect for many use cases. Simplify the code
by removing the CONFIG_CIFS_SMB311 ifdef so users don't disable
it in the build, and create compatibility and/or security issues
with modern servers - many of which have been supporting this
dialect for multiple years.
Also clarify some of the Kconfig text for cifs.ko about
SMB3.1.1 and current supported features in the module.
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
allow disabling cifs (SMB1 ie vers=1.0) and vers=2.0 in the
config for the build of cifs.ko if want to always prevent mounting
with these less secure dialects.
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Jeremy Allison <jra@samba.org>
If user specifies "posix" on an SMB3.11 mount, then fail the mount
if server does not return the POSIX negotiate context indicating
support for posix.
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
With protocol version 2.0 mounts we have seen crashes with corrupt mid
entries. Either the server->pending_mid_q list becomes corrupt with a
cyclic reference in one element or a mid object fetched by the
demultiplexer thread becomes overwritten during use.
Code review identified a race between the demultiplexer thread and the
request issuing thread. The demultiplexer thread seems to be written
with the assumption that it is the sole user of the mid object until
it calls the mid callback which either wakes the issuer task or
deletes the mid.
This assumption is not true because the issuer task can be woken up
earlier by a signal. If the demultiplexer thread has proceeded as far
as setting the mid_state to MID_RESPONSE_RECEIVED then the issuer
thread will happily end up calling cifs_delete_mid while the
demultiplexer thread still is using the mid object.
Inserting a delay in the cifs demultiplexer thread widens the race
window and makes reproduction of the race very easy:
if (server->large_buf)
buf = server->bigbuf;
+ usleep_range(500, 4000);
server->lstrp = jiffies;
To resolve this I think the proper solution involves putting a
reference count on the mid object. This patch makes sure that the
demultiplexer thread holds a reference until it has finished
processing the transaction.
Cc: stable@vger.kernel.org
Signed-off-by: Lars Persson <larper@axis.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
if mounting as smb3 do not allow cifs (vers=1.0) or insecure vers=2.0
mounts.
For example:
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1
root@smf-Thinkpad-P51:~/cifs-2.6# umount /mnt
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1,vers=1.0
mount: /mnt: wrong fs type, bad option, bad superblock on //127.0.0.1/scratch ...
root@smf-Thinkpad-P51:~/cifs-2.6# dmesg | grep smb3
[ 4302.200122] CIFS VFS: vers=1.0 (cifs) not permitted when mounting with smb3
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1,vers=3.11
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Sachin Prabhu <sprabhu@redhat.com>
cifs->master_tlink is NULL against Win Server 2016 (which is
strange.. not sure why) and is dereferenced in cifs_sb_master_tcon().
move master_tlink getter to cifsglob.h so it can be used from
smb2misc.c
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
With offset defined in rdata, transport functions need to look at this
offset when reading data into the correct places in pages.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Separate out all the 4 byte rfc1002 headers so that they are no longer
part of the SMB2 header structures to prepare for future work to add
compounding support.
Update the smb3 transform header processing that we no longer have
a rfc1002 header at the start of this structure.
Update smb2_readv_callback to accommodate that the first iovector in the
response is no the smb2 header and no longer a rfc1002 header.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
If "posix" (or synonym "unix" for backward compatibility) specified on mount,
and server advertises support for SMB3.11 POSIX negotiate context, then
enable the new posix extensions on the tcon. This can be viewed by
looking for "posix" in the mount options displayed by /proc/mounts
for that mount (ie if posix extensions allowed by server and the
experimental POSIX extensions also requested on the mount by specifying
"posix" at mount time).
Also add check to warn user if conflicting unix/nounix or posix/noposix specified
on mount.
Signed-off-by: Steve French <smfrench@gmail.com>
To improve security it may be helpful to have additional ways to restrict the
ability to override the default dialects (SMB2.1, SMB3 and SMB3.02) on mount
with old dialects (CIFS/SMB1 and SMB2) since vers=1.0 (CIFS/SMB1) and vers=2.0
are weaker and less secure.
Add a module parameter "disable_legacy_dialects"
(/sys/module/cifs/parameters/disable_legacy_dialects) which can be set to
1 (or equivalently Y) to forbid use of vers=1.0 or vers=2.0 on mount.
Also cleans up a few build warnings about globals for various module parms.
Signed-off-by: Steve French <smfrench@gmail.com>
Previous patches "cifs: update calc_size to take a server argument"
and
"cifs: add server argument to the dump_detail method"
were broken if CONFIG_CIFS_DEBUG2 enabled
Signed-off-by: Steve French <smfrench@gmail.com>
CC: Ronnie Sahlberg <lsahlber@redhat.com>
Steve French